ABSTRACT
Intramedullary nailing is used to stabilize distal femoral, proximal tibial, and distal tibial periarticular fractures with short proximal or distal segments, as well as some intra-articular fractures in which a stable articular block can be created. Intramedullary nailing may be beneficial in complex fracture patterns with diaphyseal extension, segmental injuries, or patients who might benefit from a decreased incision burden. Step 1: Preoperative planning. Review imaging and make sure there is a nail with adequate interlocks. Consider the use of adjunctive techniques to obtain and maintain alignment, and how intra-articular fracture lines will be stabilized. Step 2: Position and prepare the patient. Step 3: Exposure for nailing via suprapatellar, infrapatellar, or knee arthrotomy approaches. Limited exposure of fracture planes may also be necessary for adjunctive techniques. Step 4: Convert an OTA/AO C-type fracture to an A-type fracture if needed. Step 5: Obtain appropriate starting point and trajectory with the nail starting wire and use the opening reamer. Step 6: Obtain reduction, if not yet done, and pass the ball-tipped reaming wire across the fracture. Step 7: Ream while holding reduction. Step 8: Pass nail. Step 9: Verify reduction is maintained and correct if needed. Step 10: Place interlocks, preferably multiplanar, in the short segment. Create a fixed angle construct if desired and convert adjunctive techniques/provisional fixation to definitive fixation as needed. Step 11: Perform final checks. Step 12: Closure. Step 13: Postoperative plan. For extra-articular fractures, one may expect healing with maintained alignment from what was present at the case end intraoperatively in the vast majority of cases. For intra-articular fractures, development of posttraumatic arthritis is an additional concern.
ABSTRACT
In house flies, Musca domestica L., eggs fertilized with sperm that have chromosome deficiencies and duplications do not hatch, but develop to a stage where a fully differentiated, prehatch larva is formed. Fifteen different chromosome translocations involving most of the 10 arms of the 5 autosomes were studied by crossing male translocation heterozygotes to normal females. Egg hatch was reduced to 36-66% depending on the translocation used. Eggs that did not hatch after 24 hours were fixed, stained, and examined for stage of development. Several translocations involving the right arm of chromosome 4 indicate that the region closest to the centromere contains genes that affect the process of syngamy or early cleavage divisions, but do not reduce the ability of the sperm to compete for egg fertilization. Approximately 70% of the autosomal genes can be absent from sperm (not simultaneously but in different crosses) without inhibiting embryonic development.